Fully opening cover of sheet metal for cans

ABSTRACT

This disclosure relates to a full opening easy opening closure which has an end panel with a graduated spring profile which facilitates expansion and contraction as may occur during the sterilization of a product within a closed container. In order that this spring profile may have no undesirable action which may cause premature opening of the container, the end panel is provided with a shock absorbing bead adjacent the chuck wall and the pull tab is mounted on a platform which extends radially into the spring profile areas, but is not affected thereby.

U United States Patent [151 3,674,171 Fahlbusch July 4, 1972 [54] FULLYOPENING COVER OF SHEET [56] References Cited METAL FOR CANS UNITEDSTATES PATENTS [72] inventor: Hans Joachim Fahlbusch, Vechelde, Ger-3,400,853 9/1968 Jacobsen ..220/66 many 3,501,046 3/1970 Jasper et al...220/54 [73] Assignee: schmusaltllzag-Lubeca-werke Alrtien- PrimaryEmminer George "an AttorneyDiller, Brown, Ramik & l-lolt 22 Filed: Dec.7, 1970 [57] ABSTRACT [21] Appl. No.: 95,551

This disclosure relates to a full opening easy opening closure which hasan end panel with a graduated spring profile which Foreign ApplicationDill I facilitates expansion and contraction as may occur during the 81969 Germany G 69 47 543 0 sterilization of a product within a closedcontainer. In order that this spring profile may have no undesirableaction which may cause premature opening of the container, the end panelSil. is provided with a Shock absorbing bead adjacent the chuck [58]Field 0 Search 220/59 48 66 wall and the pull tab is mounted on aplatform which extends radially into the spring profile areas, but isnot affected thereby.

7 Claims, 3 Drawing Figures PA'TENTEDJIIH m2 3. 674, 17 1 I INVENTDRHANS Joncmm FQHLBUSCH ATTORNEYS FULLY OPENING COVER OF SHEET METAL FORCANS The invention concerns a fully rip-open cover of sheet metal forcans or similar containers with a score or indented line running nearthe chuck wall of the cover and concentrically to it, and a pull tabattached by means of a rivet to the cover surface, which lies above asector of the score line with one break-open edge.

BACKGROUND OF THE INVENTION Full opening covers for cans are known,where a single score line runs close to the chuck wall of the cover andconcentrically to it. It has furthermore been known to attach a pull tabto the area which can be torn open in such a way that a ruptureinitiating edge will lie above the score line, while the tab extendsradially to said score line and constitutes a rigid lever which at itsfree end has a section of a handle.

Furthermore, containers which can be opened easily, have been known,especially for drinks, where a radial tear strip is limited in the coversurface by score lines. There a pull tab has likewise been attached. Inorder to keep the chuck wall of the cover as free as possible of outsideforces, it has been known to provide a concentric dampening or shockabsorbing bead projecting to the inside immediately succeeding the chuckwall in the case of these cans, which elastically absorbs the movementsof the cover surface under the influence of outside or inside forces.

It has furthermore been known in the case of standard cans for cannedgoods to provide a graduated profile in the closure, which serves toincrease the absorption of volume changes during sterilization byallowing the closure to assume a position arched to the outside.

SUMMARY OF THE INVENTION It is the purpose of the present invention tocontinue to develop a full opening cover of the type designated in moredetail initially in such a manner, that on the one hand the cover willshow a good capacity for absorption of volume changes duringsterilization, without increasing the danger of a premature ripping openof the cover along the score line, and on the other hand makes possiblean attachment of the required tab, without the movements of the coversurface leading to a premature breaking open of the cover along thescore line via the pull tab.

According to the invention this problem will be solved through thecombination of the following characteristics, namely:

a. that the score line runs closely along the place of transitionbetween a dampening bead limited on the outside by the chuck wall andthe cover surface on end panel,

b. the cover surface at a radial distance from the score line has in itscross section a spring profile graduated from the outside to the insidein the manner of terraces defined by several concentric beads orshoulders, and

c. a platform for the attachment of the pull tab which projects from theedge area of the cover surface containing the score line and extendingradially inwardly and at the same level as said edge area.

Profiling of the cover surfaces like terraces does not only fulfill theknown purpose of absorbing volume, but, in conjunction with thereinforcement of the area receiving the score line by the dampening beadwill lead to the surprising consequence that the intended springmovements of the cover surface remain restricted largely to the centralarea of the cover surface, so that as a result the metal of the coveralong the score line is not put under stress. To this must be added thatas a result of the dampening bead, the spring movements, insofar as theydo continue to the edge area, are absorbed by the dampening bead,without there being any mechanical load on the score line at all.

The reinforcement of the edge area in which the score line is located isincreased further by the radially extending platform, which serves forthe attachment of the pull tab. This platform pennits a secure andreliable attachment of the tab, and this is accomplished in such a waythat it will remain in parallel to the central area of the coversurface, whereby the end of the handle portion of the tab lies at aslight distance above the deepest part of the cover surface, so that thepull tab can easily be grasped. Surprisingly, it turned out that thisplatform either does not influence the spring movement of the cover ormerely changes its shape and position insignificantly in the case ofthese spring movements of the cover, so that the spring movements of thecover remain without any influence on the pull tab. Therefore, there isno danger for the spring movements of the cover to lead via the pull tabto a premature ripping open of the cover along the score line.

Advantageously the platform at its end pointing toward the center of theclosure extends generally conically into the deepest part of the surfacecover, so that this portion of the platform represents practically acontinuous prolongation of the slanting shoulder lying the farthestinside.

The invention will be explained in more detail subsequently by way of anembodiment and on the basis of a schematic drawing.

FIG. 1 is a top view of a closure according to the invention prior tothe attachment of the pull tab.

FIG. 2 is a vertical sectional view through the lid of FIG. 1 on anenlarged scale.

FIG. 3 is an enlarged partial top view of the closure with a pull tabattached.

With reference to the drawing, a container 1 with a closure 2 connectedthereto by a double seam 3 is shown in FIGS. 1 and 2. The closure 2 hasa chuck wall 4 forming part of the double seam 3, which has immediatelyadjacent thereto a dampening bead 5 running concentrically over theentire periphery. Immediately adjacent the place of transition betweenthe dampening bead 5 and the closure end surface on end panel there is ascore or indented line 6 disposed in concentric relation to the edge. Afirst concentric shoulder 9 fol-' lowed by two more shoulders 10 and 1 lat spaced intervals lies inside the cover surface at a noticeabledistance from the score or weakening line 6, so that the cover surfaceviewed in cross section has a terrace shaped profile lowered to theinside, as can be seen best from the right half of FIG. 2.

From the edge area, which is confined between the outside shoulder 9 andthe dampening bead 5, a radial platform 12 projects radially inwardly.The platfon-n 12 is at the same level as the edge area in which thescore line 6 lies. Means for attachment of the pull tab has beenprovided in the platform and in the case of the example shown is a rivet7 which is molded out of the metal of the lid.

The platform 12 ends just in front of the central surface part 8 in afront wall 13, that runs approximately conically and which forms acontinuous prolongation of the innermost shoulder 11. The latform isbordered furthermore by lateral slanting shoulders 14, which rungenerally parallel to a radial line and which on the one hand pass overdirectly into the outward shoulder 9 and on the other hand end in thelast platform between the shoulders 10 and 11 or the inside shoulder 11,respectively.

The terrace-like area constitutes the spring part of the closure, whichcan arch outwardly, thereby considerably increasing the volume of thecontainer. The platform 12 practically does not participate in thisspring movement, and neither does the outside edge area, which liesbetween the outside shoulder 9 and dampening bead 5 and in which thescore line 6 has been provided. This outside edge area does also remainat the same time essentially free of forces which could lead to apremature ripping open of the score line 6. Any possible forces actingon the edge area are largely absorbed by the dampening bead 5, whichleads essentially to the reinforcement of the edge area. On the otherhand the platform 12 offers a secure place of attachment for the pulltab, which with its hand end projects radially inwardly beyond theplatform according to FIG. 3 and which remains above the central part 8of the closure surface so that the end of the handle of the tab can begrasped easily.

FIG. 3 is a preferred design of the handle flap, attached to the closureaccording to the invention. The tab has a ring shaped handle element 16,which is formed in one piece and rigidly with the front part ofthe tabvia the proper curlings and reinforcements, such as shoulders. At thefront end, the pull tab has a force exerting edge 17, which liesimmediately above the score line 16. In the front part there is a reces,designated as 18, in which an attaching lobe has been provided by way ofa separating line 19, which lobe is firmly connected via a joint withthe pull tab, and which at the same time, has a hole which serves forthe reception of the attaching rivet. Therivet is shown in FIG. 3 in itsbeaded position and is therefore designated 20. The pull tab does notcome into contact anywhere with the spring part of the closure and doesnot therefore participate in the movement of that part. Therefore, theopening line can be immediately above the score line 6 without therebeing any danger that the closure will be ripped open prematurely. Theplatform 12 also contributes essentially to the reinforcement of theedge area of the lid in which the score line is formed. The springmovements remain restricted to the center part of the closure. Thecentral part 8 of the closure or lid has a considerable distance fromthe section 16 ofthe handle ofthe tab, so that the latter can be graspedeasily.

What is claimed as new:

1. A full opening my opening closure comprising a seam forming portionincluding a chuck wall, a shock absorbing bead disposed immediatelyadjacent said chuck wall and surrounding an end panel, a weakening linein said end panel adjacent said shock absorbing bead defining aremovable panel portion, said end panel within and spaced from saidweakening line having a graduated spring profile defined by a series ofconcentric axially sloping shoulders, a pull tab secured to saidremovable panel portion for facilitating the rupture of said end panelalong said weakening line and tearing out said removable panel portion,and said end panel including a substantially level platform extendingradially inwardly from the area of said shock absorbing bead inunderlying relation to said pull tab, said weakening line extendingacross said platform and said platform interrupting said concentricshoulders, v

andrneamcarriedbysaidplatforrnsecuringsaidpulltabto said removable panelportion with said platform supporting said pull tab independently offlexure of said end panel due to said spring profile.

2. The closure of claim 1 wherein said platform includes a conicalradially innermost portion merging into the central part of said endpanel.

3. The closure of claim 2 wherein the radially outermost one of saidshoulders has a portion thereof at substantially the same level as saidplatform at the point of attachment of said pull tab.

4. The closure of claim 3 wherein said radially outermost shoulderterminates into inwardly extending shoulders defining the generallyradial sides of said platform.

5. The closure of claim 3 wherein said radially outermost shouldertenninates into inwardly extending shoulders defining the generallyradial sides of said platform, and said inwardly extending shouldersterminate into said conical portion.

6. The closure of claim 1 wherein the radially outermost one of saidshoulders has a portion thereof at substantially the same level as saidplatform at the point of attachment of said pull tab.

7. The closure of claim 6 wherein said radially outennost shouldertemrinates into inwardly extending shoulders defining the generallyradial sides of said platfonn.

i l 18 l t

1. A full opening easy opening closure comprising a seam forming portionincluding a chuck wall, a shock absorbing bead disposed immediatelyadjacent said chuck wall and surrounding an end panel, a weakening linein said end panel adjacent said shock absorbing bead defining aremovable panel portion, said end panel within and spaced from saidweakening line having a graduated spring profile defined by a series ofconcentric axially sloping shoulders, a pull tab secured to saidremovable panel portion for facilitating the rupture of said end panelalong said weakening line and tearing out said removable panel portion,and said end panel including a substantially level platform extendingradially inwardly from the area of said shock absorbing bead inunderlying relation to said pull tab, said weakening line extendingacross said platform and said platform interrupting said concentricshoulders, and means carried by said platform securing said pull tab tosaid removable panel portion with said platform supporting said pull tabindependently of flexure of said end panel due to said spring profile.2. The closure of claim 1 wherein said platform includes a conicalradially innermost portion merging into the central part of said endpanel.
 3. The closure of claim 2 wherein the radially outermost one ofsaid shoulders has a portion thereof at substantially the same level assaid platform at the point of attachment of said pulL tab.
 4. Theclosure of claim 3 wherein said radially outermost shoulder terminatesinto inwardly extending shoulders defining the generally radial sides ofsaid platform.
 5. The closure of claim 3 wherein said radially outermostshoulder terminates into inwardly extending shoulders defining thegenerally radial sides of said platform, and said inwardly extendingshoulders terminate into said conical portion.
 6. The closure of claim 1wherein the radially outermost one of said shoulders has a portionthereof at substantially the same level as said platform at the point ofattachment of said pull tab.
 7. The closure of claim 6 wherein saidradially outermost shoulder terminates into inwardly extending shouldersdefining the generally radial sides of said platform.